// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_CDM_PPAPI_EXTERNAL_CLEAR_KEY_FFMPEG_CDM_AUDIO_DECODER_H_
#define MEDIA_CDM_PPAPI_EXTERNAL_CLEAR_KEY_FFMPEG_CDM_AUDIO_DECODER_H_

#include <stdint.h>

#include <memory>
#include <vector>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/time/time.h"
#include "media/cdm/ppapi/external_clear_key/clear_key_cdm_common.h"
#include "media/ffmpeg/ffmpeg_deleters.h"

struct AVCodecContext;
struct AVFrame;

namespace media {
class AudioTimestampHelper;
}

namespace media {
// TODO(xhwang): This class is partially cloned from FFmpegAudioDecoder. When
// FFmpegAudioDecoder is updated, it's a pain to keep this class in sync with
// FFmpegAudioDecoder. We need a long term sustainable solution for this. See
// http://crbug.com/169203
class FFmpegCdmAudioDecoder {
public:
    explicit FFmpegCdmAudioDecoder(ClearKeyCdmHost* host);
    ~FFmpegCdmAudioDecoder();
    bool Initialize(const cdm::AudioDecoderConfig& config);
    void Deinitialize();
    void Reset();

    // Returns true when |config| is a valid audio decoder configuration.
    static bool IsValidConfig(const cdm::AudioDecoderConfig& config);

    // Decodes |compressed_buffer|. Returns |cdm::kSuccess| after storing
    // output in |decoded_frames| when output is available. Returns
    // |cdm::kNeedMoreData| when |compressed_frame| does not produce output.
    // Returns |cdm::kDecodeError| when decoding fails.
    //
    // A null |compressed_buffer| will attempt to flush the decoder of any
    // remaining frames. |compressed_buffer_size| and |timestamp| are ignored.
    cdm::Status DecodeBuffer(const uint8_t* compressed_buffer,
        int32_t compressed_buffer_size,
        int64_t timestamp,
        cdm::AudioFrames* decoded_frames);

private:
    void ResetTimestampState();
    void ReleaseFFmpegResources();

    base::TimeDelta GetNextOutputTimestamp() const;

    void SerializeInt64(int64_t value);

    bool is_initialized_;

    ClearKeyCdmHost* const host_;

    // FFmpeg structures owned by this object.
    std::unique_ptr<AVCodecContext, ScopedPtrAVFreeContext> codec_context_;
    std::unique_ptr<AVFrame, ScopedPtrAVFreeFrame> av_frame_;

    // Audio format.
    int samples_per_second_;
    int channels_;

    // AVSampleFormat initially requested; not Chrome's SampleFormat.
    int av_sample_format_;

    // Used for computing output timestamps.
    std::unique_ptr<AudioTimestampHelper> output_timestamp_helper_;
    int bytes_per_frame_;
    base::TimeDelta last_input_timestamp_;

    // Number of output sample bytes to drop before generating output buffers.
    // This is required for handling negative timestamps when decoding Vorbis
    // audio, for example.
    int output_bytes_to_drop_;

    typedef std::vector<uint8_t> SerializedAudioFrames;
    SerializedAudioFrames serialized_audio_frames_;

    DISALLOW_COPY_AND_ASSIGN(FFmpegCdmAudioDecoder);
};

} // namespace media

#endif // MEDIA_CDM_PPAPI_EXTERNAL_CLEAR_KEY_FFMPEG_CDM_AUDIO_DECODER_H_
